Many hydrocarbonaceous mineral streams contain some small proportion of diamondoid compounds. These high boiling, saturated, three-dimensional polycyclic organics are illustrated by adamantane, diamantane, triamantane and various side chain substituted homologues, particularly the methyl derivatives. These compounds have high melting points and high vapor pressures for their molecular weights and have recently been found to cause problems during production and refining of hydrocarbonaceous minerals, particularly natural gas, by condensing out and solidifying, thereby clogging pipes and other pieces of equipment. For a survey of the chemistry of diamondoid compounds, see Fort, Jr., Raymond C., "The Chemistry of Diamond Molecules," Marcel Dekker, 1976.
In recent times, new sources of hydrocarbon minerals have been brought into production which, for some unknown reason, have substantially larger concentrations of diamondoid compounds. Whereas in the past, the amount of diamondoid compounds has been too small to cause operational problems such as production cooler plugging, now these compounds represent a larger problem. The presence of diamondoid compounds in natural gas has been found to cause plugging in the process equipment requiring costly maintenance downtime to remove.
A publication by W. J. King entitled "Operating Problems in the Hanlan Swan Hills Gas Field," (SPE No. 17761, 1988), discloses a method for removing diamondoid deposits from an aerial inlet cooler using solvents.
U.S. Pat. Nos. 4,952,747; 4,952,748; and 4,952,749, all issued to Alexander et al. and are all hereby incorporated by reference. Patent No. '748 teaches a method of extracting diamondoids from a gas stream by mixing the gas stream with a solvent. Further extraction by means of a silica gel is also disclosed. Patent '747 adds a heat exchange process. Patent '749 teaches a method of diamondoid extraction that requires contacting the gas stream with a porous solid such as a zeolite whereby the zeolite absorbs some of the diamondoids.
U.S. Pat. No. 5,019,665, issued to Partridge et al. discloses a method for concentrating diamondoid compounds that exist in a solvent, during a refinery process. A solvent that is enriched in diamondoid compounds is contacted with a shape-selective catalyst under refinery conversion conditions to prevent conversion of the diamondoid compounds and to yield a solvent that is now concentrated with the isolated diamondoid compounds.
However, none of the above methods teaches the use of a multi-stage contacting device, whereby the diamondoid enriched fluid is flowed countercurrently past a suitable solvent. The prior work is therefore limited in the attempts at diamondoid extraction. There is therefore a need for an efficient, economic procedure to safely extract diamondoid compounds from hydrocarbonaceous fluids such as a natural gas stream.